There are a wide variety of electrical wiring systems for transmitting various types of electrical signals. Depending on the type of signal being transmitted along a wire, a selected type of wire is used to give the best performance in a particular environment. Wire types are selected to provide better noise immunity, for instance, and power wires must have a proper gauge to withstand a driven current.
When wiring newly constructed buildings, such as a residential home, wires used for different purposes most often are wired separately. For instance, telephone wiring, security wiring, entertainment system wiring, built-in communication system wiring and the normal power wiring have been installed separately. These installations are costly and difficult to repair once installed.
In order to provide more efficient wiring systems that solve the problems inherent to the separate system described above, and to provide a more uniform wiring system, a single hybrid ribbon cable assembly has been developed. A few examples of such hybrid ribbon cable assemblies are shown in U.S. Pat. Nos. 5,053,583 to Miller et al, dated Oct. 1, 1991; 5,057,646 to Nichols et al, dated Oct. 15, 1991; 5,097,099 to Miller, dated Mar. 17, 1992; and 5,162,611 to Nichols, III, dated Nov. 10, 1992. All of these patents show some form or another of a hybrid ribbon cable assembly wherein 60 hertz 110 volt power conductors are integrated in the same ribbon cable assembly with small gauge data conductors which may be provided for transmitting digital data communications, for instance.
One of the problems that have been encountered with hybrid ribbon cable assemblies which combine data and power wire conductors or cables is that during spikes in the current flow on the power conductors, electrical currents may be generated in the data conductors or cables creating faulty data impulses. Heretofore, attempts have been made to employ flexible metal shields completely surrounding the data conductors. The shields were formed of aluminum foil on one or both sides of a plastic film. However, this arrangement is not possible if the group of data conductors and the group of power conductors, both of which are held together with insulating material, are to remain joined together at the connection portion of insulating material. In an attempt to shield the data conductors, both the data and power conductors of the hybrid cable have been enveloped by the shield. The hybrid cable and shield was formed into a more usable C-shaped geometry. In this C-shaped form, the data and power conductors are located adjacent one another such that the data conductors are within the magnetic field of the power conductors. In this configuration these shields, although able to shield capacitive interference (i.e. high frequency interference), are inadequate to shield the data conductors from inductive coupling (i.e. low frequency interference). In other words, simply wrapping the data and power conductors in an electrically conductive film, such as of aluminum or copper, has proven inadequate.
The present invention is directed to solving these problems by providing a unique shielded hybrid ribbon cable assembly which includes a shielding means of high permeability.